Place all the ingredients in a vacuum seal bag or freezer bag (if using the water displacement method).
Vacuum seal and cook for 24 hours. Remove from the water bath and place in an ice bath for 10-15 minutes.
Remove the pork from the bag (reserve the juice) and shred it on a baking sheet.
Place it under the broiler until the edges crisp. Flip a couple of times to get crisp spots all around (be careful as you don't want it all to be crisp or it will be dry).
Drizzle with reserved bag sauce and serve on tortillas with salsa, cotija cheese, red onion, fresh cilantro and salsa and some pickled Mexican carrots on the side (optional).
Notes
You can use boneless or bone-in pork shoulder.
Please don’t skip the step of removing the air from the bag. This will keep bacteria out of the bag, especially for long cooks like this pork.
Since the pork cooks for 24 hours, it’s important to make sure the water level stays high enough so the pork stays submerged in water. Cover the water bath to minimize water evaporation.
If the pork shoulder floats in the water bath, just open the bag to let the excess air out, then reseal it.
To prevent floating, you can weigh the bag down with a sous vide sinker weight or something heavy like a wet towel.
Be careful not to broil the shredded pork for too long as it may dry out. You’ll also want to flip it a couple of times to ensure evening browning.
If you prefer, you can crisp the pork in a skillet over high heat instead of broiling.
You may need to crisp the pork in two batches depending on the size of your sheet pan or skillet.